The present invention relates to disklike recording means of the hub chucking type so called, i.e. disklike recording means fixed to disk tables of recording/reproducing devices through center hubs mounted in center holes of recording-means main bodies.
FIGS. 29-30 show one of the known hub-chucking type disklike recording means. Referring to FIGS. 29-30, a disklike recording means 101 includes a main body 102 having a signal recording face and a center hub 103 mounted in a center hole 102a of the main body 102.
The recording-means main body 102 is made of a rigid material such as synthetic resin or glass to be shaped like a disk having a center hole.
The center hub 103 is made of a magnetic metal plate such as iron plate to be shaped like a bottomed cylinder. The center hub 103 is formed with a flange 103a.
The center hub 103 is mounted to the recording-means main body 102 by inserting the cylinder 103b connected to the flange 103a in the center hole 102a of the main body 102, then joining the flange 103a to the upper side of the main body 102 by an adhesive 104.
Referring to FIG. 30, when inserting the disklike recording means 101 into a recording/reproducing device, the center hub 103 is attracted by a magnet 202 arranged to a disk table 20130 of the device, so that the disklike recording means 101 is chucked or held on a hub support face 203 of the disk table 201.
However, due to its structure that the center hub 103 of a metal plate is joined to the recording-means main body 102 of a rigid material by the adhesive 104, the known disklike recording means 101 produces the following inconveniences:
First, the recording-means main body 102 and the center hub 103 having different thermal expansion coefficients are firmly joined to each other by the adhesive 104, so that when the disklike recording means 101 is exposed to an atmosphere of high temperature, the main body 102 will be warped or deformed due to the difference in the thermal expansion coefficient. With the disklike recording means 101 having high capacity based on high-density recording, such slight warp or deformation is sufficient to produce inconveniences such as inferior recording and reproducing.
Second, after solidification of the adhesive 104, the mounting position of the center hub 103 with respect to the recording-means main body 102 is difficult to be corrected.
It is, therefore, an object of the present invention to provide disklike recording means which produce no warp or deformation in the recording-means main body due to temperature rise, etc., and ensure easy correction of the mounting position of the center hub with respect to the recording-means main body.